[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the p...[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the physical and chemical properties of target strains and in vitro antibacterial effects were measured. Moreover, the safety test of chicks was conducted. [Result] Four strains of lactobacillus were isolated from the jejunum of laying hens, including Lactobacillus plantarum, Bacillus acidophilus, L. delbrueckii subsp. Delbrueckii and L. delbrueckii subsp. Lactis, and their inhibition zone diameters were 18.30, 16.07, 11.45, 17.26 mm, respectively. One strain of Lactobacillus, L. brevis, was isolated from the cecum, with the inhibition zone diameter of 10.26 mm. Three strains of bacillus were isolated from the cecum, including Bacillus subtilis, B. cereus and B. licheniformis, and their inhibition zone diameters were 9.25, 8.46 and 8.37 mm, respectively. Daily drinking 2 billion units of viable bacteria was the safe dosage for chicks. [Conclusion] Eight strains of probiotics had certain inhibitory effect on Escherichia coli O;, and had no toxic side effects to chicks. Lactobacillus had strong antibacterial effect on E. coli O;, while the antibacterial effect of bacillus was relatively weak.展开更多
Along with the living environment,organisms have evolved structures that adapt to specific environments and have better mechanical properties.Bioinspired materials learn from nature and improve their mechanical proper...Along with the living environment,organisms have evolved structures that adapt to specific environments and have better mechanical properties.Bioinspired materials learn from nature and improve their mechanical properties by imitating the structure of living organisms.Based on the 4D printed shape memory polymer and the bioinspired design method,this research proposes a soft and hard phase hybrid bioinspired metamaterial with shape memory effect and programmable mechanical properties.Compared with traditional nacre-like materials,bioinspired materials have adjustable characteristics of mechanical properties,impact resistance,and low-frequency vibration isolation.First,based on the constitutive relation of SMP(Shape memory polymer)material and its numerical simu-lation,an intelligent bioinspired metamaterial is designed.Subsequently,the mechanical properties and vibration isola-tion behavior and adjustability performance of multi-scale bioinspired metamaterials are explained by experiments.Finally,the adjustable functional mechanism of the deforma-tion and vibration isolation of the bioinspired metamaterial is described.The research of these bioinspired metamaterials has broad application prospects in the fields of impact protection and low-frequency vibration absorption.展开更多
IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, ever...IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, every minimal set of a C^r(r≥2) flow is trivial, but it is possible for a C^0 flow to contain non-trivial minimal sets. Thus C^0 flows on closed surfaces are more complicated than C^r(r≥2) flows.展开更多
文摘[Objective] The paper was to isolate and identify probiotics in the intestine of laying hens. [Method] The intestinal probiotics in laying hens at peak period were isolated using conventional separation methods; the physical and chemical properties of target strains and in vitro antibacterial effects were measured. Moreover, the safety test of chicks was conducted. [Result] Four strains of lactobacillus were isolated from the jejunum of laying hens, including Lactobacillus plantarum, Bacillus acidophilus, L. delbrueckii subsp. Delbrueckii and L. delbrueckii subsp. Lactis, and their inhibition zone diameters were 18.30, 16.07, 11.45, 17.26 mm, respectively. One strain of Lactobacillus, L. brevis, was isolated from the cecum, with the inhibition zone diameter of 10.26 mm. Three strains of bacillus were isolated from the cecum, including Bacillus subtilis, B. cereus and B. licheniformis, and their inhibition zone diameters were 9.25, 8.46 and 8.37 mm, respectively. Daily drinking 2 billion units of viable bacteria was the safe dosage for chicks. [Conclusion] Eight strains of probiotics had certain inhibitory effect on Escherichia coli O;, and had no toxic side effects to chicks. Lactobacillus had strong antibacterial effect on E. coli O;, while the antibacterial effect of bacillus was relatively weak.
基金National Natural Science Foundation of China[52225108,52171290 and 12202065]。
文摘Along with the living environment,organisms have evolved structures that adapt to specific environments and have better mechanical properties.Bioinspired materials learn from nature and improve their mechanical properties by imitating the structure of living organisms.Based on the 4D printed shape memory polymer and the bioinspired design method,this research proposes a soft and hard phase hybrid bioinspired metamaterial with shape memory effect and programmable mechanical properties.Compared with traditional nacre-like materials,bioinspired materials have adjustable characteristics of mechanical properties,impact resistance,and low-frequency vibration isolation.First,based on the constitutive relation of SMP(Shape memory polymer)material and its numerical simu-lation,an intelligent bioinspired metamaterial is designed.Subsequently,the mechanical properties and vibration isola-tion behavior and adjustability performance of multi-scale bioinspired metamaterials are explained by experiments.Finally,the adjustable functional mechanism of the deforma-tion and vibration isolation of the bioinspired metamaterial is described.The research of these bioinspired metamaterials has broad application prospects in the fields of impact protection and low-frequency vibration absorption.
文摘IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, every minimal set of a C^r(r≥2) flow is trivial, but it is possible for a C^0 flow to contain non-trivial minimal sets. Thus C^0 flows on closed surfaces are more complicated than C^r(r≥2) flows.
